Published: Monday, February 11, 2013 at 11:23 p.m.

Last Modified: Monday, February 11, 2013 at 11:23 p.m.

RIVERSIDE, Calif. — Hundreds of tips prompted by a $1 million reward poured in to authorities seeking help finding the most wanted man in America, an ex-Los Angeles police officer who was charged Monday with murdering a Riverside policeman.

With thousands of officers around Southern California searching for Christopher Dorner, prosecutors in Riverside announced charges for last week's killing. Dorner also was charged with attempted murder for wounding another officer and firing at two others, Riverside County District Attorney Paul Zellerbach said.

The manhunt for Dorner, 33, began last Wednesday when he was named the suspect in the Orange County murders of a former Los Angeles police captain's daughter and her fiance the previous weekend. Hours after police announced they were looking for him, Dorner first fired at two LAPD officers, then ambushed the Riverside officers.

“By both his words and conduct, he has made very clear to us that every law enforcement officer in Southern California is in danger of being shot and killed,” Zellerbach said at a news conference that was guarded by four officers armed with rifles.

Police say Dorner wrote a lengthy manifesto that was posted to Facebook after the double murder. He vowed deadly revenge on those in the LAPD responsible for his firing years earlier, and their families. Police now are providing protection for some 50 families thought to be targets.

The search for Dorner was focused in the mountains near Big Bear Lake about 80 miles east of Los Angeles after his burned-out truck was found there last Thursday. Authorities are searching more than 30 square miles day and night in the ski resort area and checking on roughly 600 cabins.

Police and city officials believe the reward, raised from public and private sources, will encourage citizens to stay vigilant. More than 700 tips had come in since the reward was announced.

“Now it's like the game show ‘Who Wants to be a Millionaire,'” said Anthony Burke, supervisory inspector for the U.S. Marshals regional fugitive taskforce. “Instead of one contestant, we've got 100,000, and there's only one question you have to answer. All they have to answer is where he's at, and we can take it from there.”

The wide-ranging search has created unusually heavy traffic backups at California border crossings into Mexico, as agents are more closely inspecting each car. State police in Mexico's Baja California were given photographs of Dorner and warned to consider him armed and extremely dangerous.

Zellerbach said authorities believe Dorner will emerge at some point and try to continue carrying out his vendetta.

“I don't think he's done,” Zellerbach said. “Just read his manifesto and look at his actions. He's trying to send a message, and it would be my belief that his message is not completed yet.”

Dorner was fired from the LAPD five years ago, when a department board determined that he falsely claimed another officer had kicked a suspect. Randal Quan represented him during the proceeding.

Quan's daughter, Monica, and her fiance, Keith Lawrence, were found shot dead Feb. 3 in a car in the parking structure of their Irvine condominium. Last Wednesday, after discovery of the manifesto, Irvine police announced they were searching for Dorner.

Early Thursday in the Riverside County city of Corona, police say Dorner shot at two LAPD officers who had been dispatched to protect a possible target of Dorner's. One officer's head was grazed by a bullet; the other was unharmed.

Minutes later, authorities said Dorner used a rifle to ambush two Riverside officers, killing one and seriously wounding another. The slain officer was identified as Michael Crain, 34. The other officer's identity was not released to protect his family.

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